Stool seat



FIG. 1 is a perspective view of a stool seat;

FIG. 2 is a front view;

FIG. 3 is a back view;

FIG. 4 is a right side view;

FIG. 5 is a left side view;

FIG. 6 is a bottom view; and,

FIG. 7 is a top view.

The details shown in broken lines are for illustrative purposes only, and form no part of the claimed design. 

The ornamental design for a stool seat, as shown and described. 